[llvm] InstCombine: reuse shifted/added values in reassociation (PR #202563)

[Tianyi Jiao via llvm-commits]

squirrel1027 wrote:

Requesting review from InstCombine/Transforms maintainers: @llvm/pr-subscribers-llvm-transforms.\n\nThis PR adds a targeted lit regression test that verifies InstCombine reuses shifted/added values during reassociation. Please assign or request the appropriate reviewer(s).

https://github.com/llvm/llvm-project/pull/202563